Light-emitting dies incorporating wavelength-conversion materials and related methods

• US 9,472,732 B2
• Filed: 10/09/2015
• Issued: 10/18/2016
• Est. Priority Date: 01/24/2012
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Cooledge Lighting Inc.
• Inventors: Tischler, Michael A.
• Primary Examiner(s): GREEN, TELLY D
• Application Number:
  US14/879,503
• Publication Number:
  US 20160099389A1
• Time in Patent Office: 375 Days
• Field of Search: 257/88, 438/25, 438/27, 438/28, 438/29, 438/31, 313/501
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/04105 Bonding areas formed on an encapsulation of the semiconductor or solid-state body, e.g. bonding areas on chip-scale packages
• CPC Class Codes: H01L 2224/1403 Bump connectors having different sizes, e.g. different diameters, heights or widths
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 24/96 the devices being encapsulated in a common layer, e.g. neo-wafer or pseudo-wafer, said common layer being separable into individual assemblies after connecting
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/07802 not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/07811 Extrinsic, i.e. with electrical conductive fillers
• CPC Class Codes: H01L 2924/12032 Schottky diode
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/12043 Photo diode
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/1815 Shape
• CPC Class Codes: H01L 2924/18161 of a flip chip
• CPC Class Codes: H01L 2933/0033 relating to semiconductor body packages
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 31/055 where light is absorbed and re-emitted at a different wavelength by the optical element directly associated or integrated with the PV cell, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/505 : characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/54 : having a particular shape
• CPC Class Codes: H01L 33/56 : Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/58 : Optical field-shaping elements
• CPC Class Codes: H01L 33/60 : Reflective elements
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: Y02E 10/52 : PV systems with concentrators

Abstract

In accordance with certain embodiments, semiconductor dies are embedded within polymeric binder to form, e.g., freestanding white light-emitting dies and/or composite wafers containing multiple light-emitting dies embedded in a single volume of binder.

Claims

1. An electronic device comprising:

a solid shaped volume of a polymeric binder;

suspended within the polymeric binder, a semiconductor die having a first face, a second face opposite the first face, and at least one sidewall spanning the first and second faces, the semiconductor die being a bare-die light-emitting element comprising a plurality of active semiconductor layers that cooperatively emit light;

a reflecting layer disposed between the polymeric binder and the semiconductor die; and

disposed over the first face of the semiconductor die, at least two spaced-apart contacts each (i) having a free terminal end not covered by the polymeric binder, (ii) being available for electrical connection, and (iii) contacting a different active semiconductor layer of the semiconductor die,

wherein (i) at least a portion of the polymeric binder is transparent to a wavelength of light emitted by the light-emitting element and (ii) the reflecting layer has a reflectivity of at least 50% to a wavelength of light emitted by the light-emitting element within the polymeric binder.

2. The electronic device of claim 1, wherein the reflecting layer is disposed over a surface of the semiconductor die.

3. The electronic device of claim 1, wherein the reflecting layer is disposed over at least a portion of the first face of the semiconductor die.

4. The electronic device of claim 3, wherein the reflecting layer is disposed over at least a portion of at least one of the spaced-apart contacts.

5. The electronic device of claim 1, wherein the reflecting layer is at least a portion of at least one of the two spaced-apart contacts.

6. The electronic device of claim 1, wherein (i) the reflecting layer comprises first and second electrically insulated portions, (ii) the first portion of the reflecting layer comprises at least a portion of a first one of the at least two contacts, and (iii) the second portion of the reflecting layer comprises at least a portion of a second one of the at least two contacts.

7. The electronic device of claim 1, wherein at least a portion of the reflecting layer is electrically conductive.

8. The electronic device of claim 7, wherein the reflecting layer is disposed over a portion of at least one of the spaced-apart contacts.

9. The electronic device of claim 8, wherein (i) the reflecting layer comprises first and second electrically insulated portions, (ii) the first portion of the reflecting layer is disposed over at least a portion of a first one of the at least two contacts, and (iii) the second portion of the reflecting layer is disposed over at least a portion of the second one of the at least two contacts.

10. The electronic device of claim 1, wherein (i) the reflecting layer comprises first and second electrically insulated portions, (ii) the first portion of the reflecting layer is disposed over at least a portion of a first one of the at least two contacts, and (iii) the second portion of the reflecting layer is disposed over at least a portion of the second one of the at least two contacts.

11. The electronic device of claim 1, further comprising:

a second reflecting layer (i) having a reflectivity of at least 50% to light emitted by the light-emitting element, (ii) disposed over a portion of the polymeric binder, and (iii) disposed over and electrically coupled to a first one of the at least two contacts; and

a third reflecting layer (i) having a reflectivity of at least 50% to light emitted by the light-emitting element, (ii) disposed over a portion of the polymeric binder, (iii) disposed over and electrically coupled to a second one of the at least two contacts, and (iv) electrically insulated from the second reflecting layer.

12. The electronic device of claim 1, further comprising:

a first electrically conductive layer (i) having a reflectivity of at least 50% to light emitted by the light-emitting element, (ii) disposed over a portion of the polymeric binder, and (iii) disposed over and electrically coupled to a first one of the at least two contacts; and

a second electrically conductive layer (i) having a reflectivity of at least 50% to light emitted by the light-emitting element, (ii) disposed over a portion of the polymeric binder, (iii) disposed over and electrically coupled to a second one of the at least two contacts, and (iv) electrically insulated from the second reflecting layer.

13. The electronic device of claim 1, further comprising a second reflecting layer, wherein the second reflecting layer is disposed on a surface of the polymeric binder or disposed within at least a portion of the polymeric binder proximate the semiconductor die.

14. The electronic device of claim 13, wherein the polymeric binder contains therein a wavelength-conversion material for absorption of at least a portion of light emitted from the semiconductor die and emission of converted light having a different wavelength, converted light and unconverted light emitted by the light-emitting element combining to form mixed light.

15. The electronic device of claim 14, wherein the second reflecting layer has a reflectivity of at least 50% to light emitted by at least one of the light-emitting element or the wavelength-conversion material.

16. The electronic device of claim 1, wherein the polymeric binder contains therein a wavelength-conversion material for absorption of at least a portion of light emitted from the semiconductor die and emission of converted light having a different wavelength, converted light and unconverted light emitted by the light-emitting element combining to form mixed light.

17. The electronic device of claim 16, wherein the reflecting layer has a reflectivity of at least 50% to a wavelength of light emitted by the wavelength-conversion material.

18. The electronic device of claim 16, comprising

a second reflecting layer (i) having a reflectivity of at least 50% to light emitted by at least one of the light-emitting element or the wavelength-conversion material, (ii) disposed over a portion of the polymeric binder, and (iii) disposed over and electrically coupled to a first one of the at least two contacts;

and

a third reflecting layer (i) having a reflectivity of at least 50% to light emitted by at least one of the light-emitting element or the wavelength-conversion material, (ii) disposed over a portion of the polymeric binder, (iii) disposed over and electrically coupled to a second one of the at least two contacts, and (iv) electrically insulated from the second reflecting layer.

19. The electronic device of claim 16, wherein the wavelength-conversion material comprises at least one of a phosphor or quantum dots.

20. The electronic device of claim 16, wherein the mixed light is substantially white light.

21. The electronic device of claim 20, wherein the substantially white light has a correlated color temperature in the range of 2000 K to 10,000 K.

22. The electronic device of claim 16, further comprising an optical element positioned to receive at least a portion of the mixed light.

23. The electronic device of claim 22, wherein the optical element is configured to distribute the mixed light in a specific light distribution pattern.

24. The electronic device of claim 22, wherein the optical element comprises at least one of a reflector, a refractive optic, a diffractive optic, a total internal reflection optic, or a Fresnel optic.

25. The electronic device of claim 1, further comprising an optical element positioned to receive at least a portion of light from the semiconductor die.

26. The electronic device of claim 1, wherein the active semiconductor layers of the semiconductor die are not disposed on a semiconductor substrate.

27. The electronic device of claim 1, wherein at least a portion of the reflecting layer is substantially parallel to the first face of the semiconductor die.

28. The electronic device of claim 1, wherein the reflecting layer has a reflectivity of at least 75% to a wavelength of light emitted by the light-emitting element.

29. The electronic device of claim 1, wherein at least portions of the contacts protrude from the polymeric binder.

30. The electronic device of claim 1, wherein the polymeric binder and the semiconductor die collectively define an approximately rectangular solid having approximately 90°

corners between adjacent faces thereof.

31. The electronic device of claim 1, wherein the polymeric binder comprises at least one of silicone or epoxy.

32. The electronic device of claim 1, further comprising one or more additional semiconductor dies suspended within the polymeric binder.

33. The electronic device of claim 1, wherein the light-emitting element comprises a semiconductor material comprising at least one of GaAs, AlAs, InAs, GaP, AlP, InP, ZnO, CdSe, CdTe, ZnTe, GaN, AIN, InN, silicon, or an alloy or mixture thereof.

34. The electronic device of claim 1, wherein the polymeric binder has a thickness between 5 μ

m and 4000 μ

m.

35. The electronic device of claim 1, wherein the polymeric binder coats the second face of the semiconductor die, the at least one sidewall, and at least a portion of the first face of the semiconductor die.

36. The electronic device of claim 1, wherein the light-emitting element comprises a light-emitting diode.

37. The electronic device of claim 1, wherein the first face of the semiconductor die comprises at least two non-coplanar portions each having at least one said contact thereon.

38. The electronic device of claim 1, wherein at least a portion of a top surface of the polymeric binder is curved.

39. The electronic device of claim 1, further comprising, at least partially suspended within the polymeric binder, at least one additional semiconductor die having a first face, a second face opposite the first face, and at least one sidewall spanning the first and second faces, each additional semiconductor die being a bare-die light-emitting element comprising a plurality of active semiconductor layers that cooperatively emit light.

40. The electronic device of claim 16, wherein the polymeric binder comprises a plurality of discrete regions, at least one of which comprises the polymeric binder without wavelength-conversion material therein.

41. The electronic device of claim 18, wherein the reflecting layer has a reflectivity of at least 75% to a wavelength of light emitted by at least one of the light-emitting element or the wavelength-conversion material.

42. The electronic device of claim 18, wherein the reflecting layer is a substantially diffuse reflector.

43. The electronic device of claim 18, wherein the reflecting layer is a substantially specular reflector.